A novel arsenic immobilization strategy via a two-step process: Arsenic concentration from dilute solution using schwertmannite and immobilization in Ca-Fe-AsO4 compounds

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:295

Article

Park, Ilhwan¹  Ryota, Takashino²  Yuto, Takeuchi²  Tabelin, Carlito Baltazar³  Phengsaart, Theerayut⁴  Jeon, Sanghee¹  Ito, Mayumi¹  Hiroyoshi, Naoki¹ 

[1] Hokkaido Univ, Div Sustainable Resources Engn, Fac Engn, Sapporo, Hokkaido 0608628, Japan

[2] Hokkaido Univ, Grad Sch Engn, Div Sustainable Resources Engn, Sapporo, Hokkaido 0608628, Japan

[3] Univ New South Wales, Sch Minerals & Energy Resources Engn, Sydney, NSW 2052, Australia

[4] Chulalongkorn Univ, Fac Engn, Dept Min & Petr Engn, Bangkok 10330, Thailand

关键词: Arsenic immobilization;    Sorption;    desorption;    Schwertmannite;    Ferric arsenate;    Yukonite;    Johnbaumite;   

DOI  :  10.1016/j.jenvman.2021.113052

来源: Elsevier

【 摘 要 】

Acid mine drainage (AMD) with toxic arsenic (As) is commonly generated from the tailings storage facilities (TSFs) of sulfide mines due to the presence of As-bearing sulfide minerals (e.g., arsenopyrite, realgar, orpiment, etc.). To suppress As contamination to the nearby environments, As immobilization by Ca-Fe-AsO4 compounds is considered one of the most promising techniques; however, this technique is only applicable when As concentration is high enough (>1 g/L). To immobilize As from wastewater with low As concentration (-10 mg/L), this study investigated a two-step process consisting of concentration of dilute As solution by sorption/desorption using schwertmannite (Fe8O8(OH)8-2x(SO4)x; where (1 < x < 1.75)) and formation of Ca-Fe-AsO4 compounds. Arsenic sorption tests indicated that As(V) was well adsorbed onto schwertmannite at pH 3 (Qmax = 116.3 mg/g), but its sorption was limited at pH 13 (Qmax = 16.1 mg/g). A dilute As solution (-11.2 mg/L As) could be concentrated by sorption with large volume of dilute As solution at pH 3 followed by desorption with small volume of eluent of which pH was 13. The formation of Ca-Fe-AsO4 compounds from As concentrate solution (2 g/L As(V)) was strongly affected by temperature and pH. At low temperature (25-50 degrees C), amorphous ferric arsenate was formed, while at high temperature (95 degrees C), yukonite (Ca2Fe3-5(AsO4)3(OH)4-10.xH2O; where x = 2-11) and johnbaumite (Ca5(AsO4)3OH) were formed at pH 8 and 12, respectively. Among the synthesized products, johnbaumite showed strongest As retention ability even under acidic (pH < 2) and alkaline (pH > 9) conditions.

【 授权许可】

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